Tom Cocca tcocca

When should you use DateTime and when should you use Time?

It's a common misconception that [William Shakespeare][1] and [Miguel de Cervantes][2] died on the same day in history - so much so that UNESCO named April 23 as [World Book Day because of this fact][3]. However because England hadn't yet adopted [Gregorian Calendar Reform][4] (and wouldn't until [1752][5]) their deaths are actually 10 days apart. Since Ruby's Time class implements a [proleptic Gregorian calendar][6] and has no concept of calendar reform then there's no way to express this. This is where DateTime steps in:

>> shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
=> Tue, 23 Apr 1616 00:00:00 +0000
>> cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
=> Sat, 23 Apr 1616 00:00:00 +0000

Note: these haven't been vetted yet

Gems and libraries

https://github.com/mattetti/GC-stats-middleware
https://github.com/bhb/rack-perftools_profiler
https://github.com/37signals/trashed (requires statsd)
https://github.com/cheald/scrap (rails metal)
https://github.com/fauna/bleak_house (requires custom ruby build and/or ruby 1.8.7, not as usable for request cycle)

	# inspired by http://askubuntu.com/a/528171 and the comments below

	# build bash 3.2, though this should work for other versions as well
	BASH_MAJOR=3
	BASH_MINOR=2

	# prerequisites
	sudo apt-get install build-essential gettext bison

	# get bash source

	# lib/tasks/db.rake
	namespace :db do

	desc "Dumps the database to db/APP_NAME.dump"
	task :dump => :environment do
	cmd = nil
	with_config do \|app, host, db, user\|
	cmd = "pg_dump --host #{host} --username #{user} --verbose --clean --no-owner --no-acl --format=c #{db} > #{Rails.root}/db/#{app}.dump"
	end
	puts cmd

	group :production do
	gem 'unicorn'

	# Enable gzip compression on heroku, but don't compress images.
	gem 'heroku-deflater'

	# Heroku injects it if it's not in there already
	gem 'rails_12factor'
	end

	{
	"query": {
	"filtered": {
	"query": {
	"match_all": {}
	},
	"filter": {
	"not": {
	"bool": {
	"must": {

	# Script to be placed in elasticsearch/bin
	# Launch it from elasticsearch dir
	# bin/backup indexname
	# We suppose that data are under elasticsearch/data
	# It will create a backup file under elasticsearch/backup

	if [ -z "$1" ]; then
	INDEX_NAME="dummy"
	else
	INDEX_NAME=$1

	class TasksController < ApplicationController
	def update
	tracker = TaskTracker.new(@task)
	if @task.update_attributes(params[:task])
	TaskPusher.new(tracker, socket_id).push_changes
	TaskMailSender.new(tracker, current_user).deliver_email
	# success response
	else
	# failure respond
	end

	#!/usr/bin/env bash

	###############FUNCTIONS############

	function prepare {
	#optimize the index
	echo -n "Optimizing index $INDEX_NAME..."
	curl -XPOST "$ADDRESS/$INDEX_NAME/_optimize" 2>/dev/null\| grep 'failed":0' >/dev/null
	if [ $? -eq 0 ]; then
	echo "done"

	If you want, I can try and help with pointers as to how to improve the indexing speed you get. Its quite easy to really increase it by using some simple guidelines, for example:

	- Use create in the index API (assuming you can).
	- Relax the real time aspect from 1 second to something a bit higher (index.engine.robin.refresh_interval).
	- Increase the indexing buffer size (indices.memory.index_buffer_size), it defaults to the value 10% which is 10% of the heap.
	- Increase the number of dirty operations that trigger automatic flush (so the translog won't get really big, even though its FS based) by setting index.translog.flush_threshold (defaults to 5000).
	- Increase the memory allocated to elasticsearch node. By default its 1g.
	- Start with a lower replica count (even 0), and then once the bulk loading is done, increate it to the value you want it to be using the update_settings API. This will improve things as possibly less shards will be allocated to each machine.
	- Increase the number of machines you have so